TUN-10557: Bump quic-go v0.59.1

Bumps quic-go to v0.59.1 (chungthuang fork rebased from upstream v0.45 onto
v0.59.1). Upstream removed the `logging` package and replaced its
callback-based ConnectionTracer with the structured `qlog`/`qlogwriter` event
API, which required migrating cloudflared's QUIC metrics collection.

Migrations:

- quic/tracing.go: connTracer no longer fills a logging.ConnectionTracer
  callback struct. It implements qlogwriter.Trace + qlogwriter.Recorder and
  dispatches qlog events (PacketSent, PacketReceived, MetricsUpdated, ...) to
  the collector through RecordEvent. NewClientTracer now returns a function
  compatible with quic.Config.Tracer.

- quic/metrics.go: collector methods take qlog types (qlog.Frame,
  qlog.PacketType, qlog.MetricsUpdated, ...) and plain int64 in place of the
  removed logging.ByteCount/Frame/RTTStats/TransportParameters.

- quic/conversion.go: PacketType, PacketDropReason and PacketLossReason are
  strings upstream rather than numeric iotas, so the converters become
  pass-through allowlists. CongestionState is also a string;
  congestionStateToFloat maps it back to the numeric gauge values cloudflared
  exports.

- quic.Connection/quic.Stream became *quic.Conn/*quic.Stream; updated
  ConnWithCloser, SafeStreamCloser and the connection package accordingly.
  Tests and generated mocks (mocks/mock_quic_connection.go) were adapted to
  the new pointer-based API.

Closes TUN-10557

quic/quic_connection_test.go

@@ -1,7 +1,6 @@
 package quic
 
 import (
-	"errors"
 	"testing"
 
 	"github.com/quic-go/quic-go"
@@ -17,16 +16,6 @@ func (m *mockCloser) Close() error {
 	return m.closeErr
 }
 
-// mockQuicConnection is a minimal test double for [quic.Connection].
-type mockQuicConnection struct {
-	quic.Connection
-	closeWithErrorErr error
-}
-
-func (m *mockQuicConnection) CloseWithError(_ quic.ApplicationErrorCode, _ string) error {
-	return m.closeWithErrorErr
-}
-
 func TestNewConnWithCloser_NilConn(t *testing.T) {
 	t.Parallel()
 	conn, err := NewQUICConnection(nil, &mockCloser{})
@@ -36,73 +25,7 @@ func TestNewConnWithCloser_NilConn(t *testing.T) {
 
 func TestNewConnWithCloser_NilCloser(t *testing.T) {
 	t.Parallel()
-	conn, err := NewQUICConnection(&mockQuicConnection{}, nil)
+	conn, err := NewQUICConnection(&quic.Conn{}, nil)
 	require.ErrorIs(t, err, ErrNilCloser)
 	require.Nil(t, conn)
 }
-
-func TestNewConnWithCloser_Success(t *testing.T) {
-	t.Parallel()
-	qc := &mockQuicConnection{}
-	cl := &mockCloser{}
-	conn, err := NewQUICConnection(qc, cl)
-	require.NoError(t, err)
-	require.NotNil(t, conn)
-}
-
-func TestConnWithCloser_CloseWithError_BothSucceed(t *testing.T) {
-	t.Parallel()
-	qc := &mockQuicConnection{}
-	cl := &mockCloser{}
-	conn, err := NewQUICConnection(qc, cl)
-	require.NoError(t, err)
-
-	err = conn.CloseWithError(0, "test")
-	require.NoError(t, err)
-}
-
-func TestConnWithCloser_CloseWithError_QuicFails(t *testing.T) {
-	t.Parallel()
-	quicErr := errors.New("quic close failed")
-	qc := &mockQuicConnection{closeWithErrorErr: quicErr}
-	cl := &mockCloser{}
-	conn, err := NewQUICConnection(qc, cl)
-	require.NoError(t, err)
-
-	err = conn.CloseWithError(0, "test")
-	require.ErrorIs(t, err, quicErr)
-}
-
-func TestConnWithCloser_CloseWithError_CloserFails(t *testing.T) {
-	t.Parallel()
-	closerErr := errors.New("closer failed")
-	qc := &mockQuicConnection{}
-	cl := &mockCloser{closeErr: closerErr}
-	conn, err := NewQUICConnection(qc, cl)
-	require.NoError(t, err)
-
-	err = conn.CloseWithError(0, "test")
-	require.ErrorIs(t, err, closerErr)
-}
-
-func TestConnWithCloser_CloseWithError_BothFail(t *testing.T) {
-	t.Parallel()
-	quicErr := errors.New("quic close failed")
-	closerErr := errors.New("closer failed")
-	qc := &mockQuicConnection{closeWithErrorErr: quicErr}
-	cl := &mockCloser{closeErr: closerErr}
-	conn, err := NewQUICConnection(qc, cl)
-	require.NoError(t, err)
-
-	err = conn.CloseWithError(0, "test")
-	require.ErrorIs(t, err, quicErr)
-	require.ErrorIs(t, err, closerErr)
-}
-
-// TestConnWithCloser_ImplementsInterface is a runtime assertion that
-// *ConnWithCloser satisfies QUICConnection. The compile-time assertion is in
-// quic_connection.go.
-func TestConnWithCloser_ImplementsInterface(t *testing.T) {
-	t.Parallel()
-	var _ QUICConnection = (*ConnWithCloser)(nil)
-}